This condition is also more properly known as congenital adrenal hyperplasia. This is a group of conditions of similar source: a family of autosomal recessive disorders of steroid hormone production in the adrenal glands leading to a deficiency of cortisol, the stress fighting hormone. The master hormonal regulatory gland, the pituitary, sensing the deficiency, secretes massive amounts of the stimulating hormone corticotropin to bring the cortisol levels up to normal. This hormone in turn causes the adrenal glands to overproduce certain intermediary hormones which have testosterone-like effects on the fetus and child, leading to so-called "virilization."
Hutchinson-Gilford progeria syndrome is a genetic condition characterized by the dramatic, rapid appearance of aging beginning in childhood. Affected children typically look normal at birth and in early infancy, but then grow more slowly than other children and do not gain weight at the expected rate (failure to thrive). They develop a characteristic facial appearance including prominent eyes, a thin nose with a beaked tip, thin lips, a small chin, and protruding ears. Hutchinson-Gilford progeria syndrome also causes hair loss (alopecia), aged-looking skin, joint abnormalities, and a loss of fat under the skin (subcutaneous fat). This condition does not disrupt intellectual development or the development of motor skills such as sitting, standing, and walking.
Hutchinson-Gilford Progeria syndrome is an extremely rare condition in which physical aspects of aging are greatly accelerated, and few affected children live past age 13. About 1 in 8 million babies are born with this condition. It is a genetic condition, but occurs sporadically and is usually not inherited in families.progeria syndrome is considered an autosomal dominant condition, which means one copy of the altered gene in each cell is sufficient to cause the disorder. The condition results from new mutations in the LMNA gene, and almost always occurs in people with no history of the disorder in their family.
Causes
Mutaion is LMNA gene causes Progeria syndrome,LMNA is a gene which povides instruction to make a parotein called Lamin A,Lamin A protein plays important role in determining the shape of the nuclues within cells,It si essential component for nuclear envelope,Mutationsin this gene causes abnormal version of lamin A protein,This altered protein makes teh nuclear envelope unstable and progressively damages the nuclues,making cells more likely to die Prematurely.
Color blindness, a color vision deficiency, is the inability to perceive differences between some of the colors that others can distinguish. It is most often of genetic nature, but may also occur because of eye, nerve, or brain damage, or due to exposure to certain chemicals. The English chemist John Dalton published the first scientific paper on the subject in 1798, "Extraordinary facts relating to the vision of colours", after the realization of his own color blindness; because of Dalton's work, the condition is sometimes called daltonism, although this term is now used for a type of color blindness called deuteranopia.
Color blindness is usually classed as disability; in certain situations, however, color blind people have an advantage over people with normal color vision. There are some studies which conclude that color blind individuals are better at penetrating certain camouflages.
Ehlers-Danlos syndrome is a group of disorders that affect connective tissues, which are tissues that support the skin, bones, blood vessels, and other organs. Defects in connective tissues cause the signs and symptoms of Ehlers-Danlos syndrome, which vary from mildly loose joints to life-threatening complications.
In 1997, researchers proposed a simpler classification that reduced the number of major types to six and gave them descriptive names: the arthrochalasia type, the classic type, the dermatosparaxis type, the hypermobility type, the kyphoscoliosis type, and the vascular type. Other forms of the condition may exist, but they have been reported only in single families or are not well characterized.
Although all types of Ehlers-Danlos syndrome affect the joints and many also affect the skin, features vary by type. An unusually large range of joint movement (hypermobility) occurs with most forms of Ehlers-Danlos syndrome, particularly the hypermobility type. Infants with hypermobile joints often appear to have weak muscle tone, which can delay the development of motor skills such as sitting, standing, and walking. The loose joints are unstable and prone to dislocation, chronic pain, and early-onset arthritis. Dislocations involving both hips are a characteristic finding in infants with the arthrochalasia type of Ehlers-Danlos syndrome.
Causes
Mutaions in ADAMTS2, COL1A1, COL1A2, COL3A1, COL5A1, COL5A2, PLOD1, and TNXB genes cause Ehlers-Danlos syndrome.Researchers have identified more than 20 mutations in PLOD1 gene in affected persons,These mutations cause a form of Ehlers-Danlos syndrome called the kyphoscoliosis type,The most common mutation duplicates a large portion of the gene, resulting in the production of a nonfunctional version of the lysyl hydroxylase 1 enzyme. Several other mutations introduce premature stop signals that prevent the gene from making any functional enzyme. A loss of lysyl hydroxylase 1 activity impairs cross-linking between collagen molecules. This disruption in the network of collagen fibrils weakens connective tissues, causing the signs and symptoms of Ehlers-Danlos syndrome.
Homocystinuria, also known as Cystathionine beta synthase deficiency which occurs 1 in 200000 to 335000 people world wide,It is an inherited disorder of the metabolism of the amino acid methionine, often involving cystathionine beta synthase.This form of homocystinuria is characterized by dislocation of the lens in the eye, an increased risk of abnormal blood clots, and skeletal abnormalities. It is an inherited autosomal recessive trait, which means a child needs to inherit the defective gene from both parents to be affected.
The CBS gene provides instructions for producing cystathionine beta-synthase. This enzyme is responsible for one step in a chemical pathway that processes the amino acid methionine. Other amino acids, including homocysteine, are also products of this pathway. Mutations in the CBS gene disrupt the function of cystathionine beta-synthase, preventing homocysteine from being used properly. As a result, this amino acid and other potentially toxic substances build up in the blood, and some of the excess homocysteine is excreted in urine.
